This invention relates to an elevator hoist apparatus and, more particularly, to an elevator hoist apparatus comprising a blower mounted on a motor frame of an electric motor for generating a flow of cooling air within a ventilation duct
The entire content of the basic Japanese Patent Application from which the priority under the Convention is claimed in this application is hereby incorporated by reference into this application.
While Japanese Patent Laid-Open No. 59-102786 discloses one example of a conventional elevator hoist apparatus, FIGS. 7 and 8 of the present application are schematic front and side views, respectively, illustrating a conventional elevator hoist apparatus to which the present invention can be applied. In these figures, the elevator hoist apparatus comprises a base 1 constructed of welded U-shaped steel beams and an electric motor 4 secured to the base 1 via leg portions 2 and having a substantially hollow cylindrical motor frame 3 including an open end in the left side of FIG. 8 and a closed end in the right side of FIG. 8.
Motor frame 3 supports at its inner surface a stator 5 of the motor 4 and supports a rotor 6 at bearings 7 disposed on both its ends. The motor frame 3 also has defined therein a ventilation passage 8 for cooling the stator 5 and the rotor 6. The ventilation passage 8 extends from an inlet suction port 9 disposed at a first axial end of the motor frame 3 in relation to an axis A of the motor frame 3, through a flow passage indicated by arrows and extending along the stator 5 and the rotor 6 to a discharge port 10 disposed at a second axial end of the motor frame 3.
The elevator hoist apparatus also comprises blowers 11 disposed to the motor frame 3 of the electric motor 4 for generating a flow (see arrows) of cooling air within the ventilation passage 8 and a sheave 12 rotatably supported by the bearings 7 in the motor frame 3 and driven by the electric motor 4. The other end of the sheave 12 is supported by a second bearing 14 on the bearing pedestal 13 secured to the base 1. Also, the bearing pedestal 13 includes a brake 15 so that a braking force may be applied to a brake disc 16 of the sheave 12.
In the conventional elevator hoist apparatus, the inlet suction port 9 of the ventilation passage 8 for the cooling air is disposed at the central portion of one axial end (left end as viewed in FIG. 8) of the motor frame 3 of the electric motor 4 and has a relatively large opening diameter as shown in FIG. 7, and two discharge ports 10 are disposed on the cylindrical portion of the motor frame 3 with their axes B at a circumferential position separated by 45 degrees for xe2x80x98examplexe2x80x99 above the horizontal plane H including the axis A of the motor frame 3. Also, the blower 11 connected to the ventilation passage 8 for dissipating the heat generated inside of the motor 4 is mounted on the outer circumferential cylindrical portion of the motor frame 3 of the electric motor 4
The elevator hoist apparatus of the present invention comprises a base and an electric motor disposed on the base. The motor has a stator, a rotor and a hollow substantially cylindrical motor frame supporting the stator and the rotor, the motor frame having defined therein a ventilation passage for cooling the stator and the rotor. The elevator hoist apparatus also comprises a blower disposed to the motor frame of the electric motor for generating a flow of cooling air within the ventilation passage and a sheave disposed to the base and driven by the electric motor. The ventilation passage comprises an inlet suction port disposed at a central portion of one axial end of the motor frame, a flow passage extending along the stator and the rotor and a discharge port disposed at the other axial end of the motor frame. The discharge port comprises an upper discharge port disposed on the motor frame at a circumferential position separated by substantially 45 degrees above from the horizontal plane including a central axis of the electric motor and a lower discharge port disposed on the motor frame at a position below the horizontal plane. Further, the blower is connected to the each of the upper discharge port and the lower discharge port, thereby generating a substantially uniform flow of cooling air within the motor frame.
The upper discharge port and the lower discharge port may be disposed on the motor frame at positions circumferentially separated by substantially 45 degrees with respect to the horizontal plane.
The blower may be disposed on an outer circumferential surface of the motor frame or on an end surface of the other end of the motor frame.
The blower connected to the lower discharge port may be mounted to the motor frame.